As Ekterly nears the one-year anniversary of its FDA approval, Italy’s Chiesi Group is making moves to acquire the rare disease med and its developer, KalVista Pharmaceuticals.
Chiesi has locked in an offer to buy out KalVista for $27 per share in cash, representing a total deal value of $1.9 billion, according to an April 29 press release. The amount floated marks the biggest transaction for Chiesi in the pharma’s nearly 100-year history and is good for a 36% premium to Kalvista’s share price on April 28, the companies said Wednesday.
Chiesi is positioning the deal, expected to close in the third quarter, as a means to bolster its standing in the rare disease arena, where the company’s business unit Chiesi Global Rare Diseases already boasts substantial operations.
The crown jewel of the transaction is Ekterly, KalVista’s oral treatment for hereditary angioedema (HAE), which bounced back from a regulatory delay to win an FDA nod last July, becoming the Massachusetts biotech’s first commercial product.
Once the deal has closed, Chiesi will assume responsibility for the drug, a plasma kallikrein inhibitor that also goes by the name sebetralstat.
HAE is a rare genetic disease that leads to deficiency or dysfunction in the C1 esterase inhibitor (C1INH) protein, which can cause painful and debilitating attacks of tissue swelling at various points in the body. Those attacks can be fatal, depending on the area of the body affected.
Unlike some medicines that are approved to help prevent HAE attacks, Ekterly is the first oral medication specifically approved for on-demand treatment of HAE attacks.
Chiesi aims to accelerate patient access and bolster scientific engagement around Ekterly. The Italian pharma expects that Ekterly will “meaningfully contribute” to its goal to hit revenues of 6 billion euros in 2030, adding that the addition of the product substantially expands its market presence in the United States.
From “day one,” in fact, Chiesi will focus on “working closely with the HAE community and the scientific community to improve disease management and ensure more patients can benefit from timely, effective treatment,” Giacomo Chiesi, EVP for Chiesi Global Rare Diseases, said in a statement.
Apart from the U.S., Ekterly has also secured green lights in the United Kingdom, Japan and the European Union. For all of 2025, representing roughly half of a full calendar year on the market following the med’s July approval, Ekterly generated $49 million in sales, according to Chiesi and KalVista’s announcement.
Chiesi has struck a number of other high-value deals and outlays since the beginning of 2025, notably putting forward 430 million euros (then worth roughly $464 million) last March to build a new facility for inhalers and other health products in Milan, while also revitalizing an older production site there.
Separately, the family-owned company in October joined in on Arbor Biotechnologies’ rare disease gene therapy efforts, shelling out $115 million upfront—plus offering hundreds of millions more in potential biobucks—for rights to develop and commercialize ABO-101, a liver-targeted gene therapy for the ultrarare genetic disease primary hyperoxaluria type 1 (PH1). The deal also allows Chiesi to use Arbor’s editing technology for other potential disease treatments.
Elsewhere in Chiesi’s commercial rare disease portfolio, the company already boasts multiple products in Filsuvez for epidermolysis bullosa, lipodystrophy med Myalept and Fabry disease treatment Elfabrio, among others.